Coaxial probe and scanning micro-wave microscope including the same

ABSTRACT

A coaxial probe includes a coaxial cable including an electrical conductor extending therethrough and projecting therefrom at an end thereof, a planar waveguide on which the electrical conductor projecting from the coaxial cable is mounted, and a sensor electrically connected to the electrical conductor through the planar waveguide. The planar waveguide may be comprised of a substrate, and a strip line formed on the substrate, the strip line being electrically connected at one end to the sensor and at the other end to the electrical conductor. The sensor may be comprised of a cantilever supported at a distal end thereof on the planar waveguide, and a probe mounted on a free end of the cantilever.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The invention relates to a coaxial probe scanning a surface of anobject with a probe to thereby monitor physical quantity such as a shapeof the surface or an electrical characteristic of the object. Theinvention further relates to a scanning micro-wave microscope includingthe above-mentioned coaxial probe for forming an image of a surface ofan object.

[0003] 2. Description of the Related Art

[0004] A scanning probe microscope has a resolution in atomic level,specifically, a resolution of an order of nanometer or smaller. Inaddition, a scanning probe microscope has a function of forming an imageof a three-dimensional shape, based on information including a profileof height of an object. Hence, a scanning probe microscope is used inmany fields.

[0005] It is assumed that a coaxial cable defining a coaxial resonatorto be excited by micro-waves is formed at an end surface thereof with anopening. If the opening of the coaxial cable is made approach a surfaceof an object, an impedance or electric coupling of the opening isvaried, and accordingly, a resonance frequency of the coaxial resonatoris shifted, and a Q-value of the coaxial resonator is also varied.

[0006] Accordingly, as a surface of an object is scanned with theopening of the coaxial cable, a resonance frequency or Q-value of thecoaxial cable is varied. As a result, it would be possible to form animage of a surface of an object, based on variation of the resonancefrequency or Q-value.

[0007] A scanning micro-wave microscope operates under theabove-mentioned principle. For instance, an example of a scanningmicro-wave microscope is suggested in Applied Physics Letters, Vol. 72,pp. 1778-1780,1989.

[0008] In operation of the suggested scanning micro-wave microscope, anopening of a coaxial cable is positioned slightly above a surface of anelectrically conductive object, the surface is scanned with the openingof the coaxial cable, it is detected how degree a frequency is shiftedin dependence on a distance between the opening of the coaxial cable andthe surface of the object, and an image of the surface of the object isformed based on the detected degree.

[0009] A scanning micro-wave microscope has an image resolution of{fraction (1/1000)} of a wavelength of a micro-wave or smaller, whichmeans that the scanning micro-wave microscope constitutes a so-calledproximity field microscope.

[0010] In particular, a point at which a resonance frequency is shiftedand/or a Q-value is varied, detected by a scanning micro-wavemicroscope, corresponds to a point at which conservation energy and/ordissipation energy of a system defined by an object and a coaxialresonator are(is) varied.

[0011] A scanning micro-wave microscope is required to have a resolutionwhich is generally equal to ½ to ¼ of a diameter detected by a tip endof an electrical conductor extending through a coaxial cable. In orderfor a scanning micro-wave microscope to have such a resolution, it wouldbe necessary for the electrical conductor to approach a surface of anobject at a distance of a diameter of the tip end of the electricalconductor or smaller.

[0012] However, in the above-mentioned conventional scanning micro-wavemicroscope, since the electrical conductor of the coaxial cable is madedirectly approach a surface of an object, a closest distance between theelectrical conductor and a surface of an object could be just fewmicrometers. If the electrical conductor is positioned relative to asurface of an object at a distance smaller than the above-mentionedclosest distance, just few micrometers, the electrical conductor mightcollide with a surface of an object or make uncontrollable contact witha surface of an object. This means that a scanning micro-wave microscopeor a proximity field microscope cannot accomplish its best performance,because it works better when it is located at a smaller distance from asurface of an object.

[0013] Japanese Unexamined Patent Publication No. 8-248322 has suggestedan attachment module for measuring a focus of an objective lens,including a plate, a support mounted on the plate, a positioning devicefor positioning an object relative to the support in two directionsperpendicular to each other, and a probe having a tip end, composed ofglass fibers and mounted on the positioning device.

[0014] Japanese Unexamined Patent Publication No. 9-178760 has suggesteda scanning probe microscope including a cantilever, a probe mounted on atip end of the cantilever, a detector for detecting physical quantityappearing between the probe and the object, a mover forthree-dimensionally moving the probe and the object, a controller forcontrolling an operation of the mover, and means for moving the scanningprobe microscope.

[0015] However, the above-mentioned problems remain unsolved even in thescanning probe microscopes suggested in the above-mentionedPublications.

SUMMARY OF THE INVENTION

[0016] In view of the above-mentioned problems in the conventionalscanning probe microscope, it is an object of the present invention toprovide a coaxial probe which is capable of making a probe approach asurface of an object at a distance of a diameter of an electricalconductor extending through a coaxial cable or smaller to therebymeasure an impedance along a surface of an object.

[0017] It is also an object of the present invention to provide ascanning probe microscope including such a coaxial probe.

[0018] In one aspect of the present invention, there is provided acoaxial probe including (a) a coaxial cable including an electricalconductor extending therethrough and projecting therefrom at an endthereof, (b) a planar waveguide on which the electrical conductorprojecting from the coaxial cable is mounted, and (c) a sensorelectrically connected to the electrical conductor through the planarwaveguide.

[0019] For instance, the planar waveguide may be comprised of (b1) asubstrate, and (b2) a strip line formed on the substrate, the strip linebeing electrically connected at one end to the sensor and at the otherend to the electrical conductor.

[0020] For instance, the planar waveguide may be comprised of (b1) asubstrate, and (b2) a coplanar line formed on the substrate, the stripline being electrically connected at one end to the sensor and at theother end to the electrical conductor.

[0021] For instance, the sensor may be comprised of (c1) a cantileversupported at a distal end thereof on the planar waveguide, and (c2) aprobe mounted on a free end of the cantilever.

[0022] It is preferable that the coaxial probe further includes asupport which fixes the cantilever at the distal end of the cantileveronto the planar waveguide.

[0023] It is preferable that the support and the cantilever are locatedon an extension of the electrical conductor and are inclined relative toan axis of the electrical conductor.

[0024] It is preferable that the sensor is excited at a frequency closeto a resonance frequency of a movement of the cantilever.

[0025] It is preferable that the sensor is detachable from the coaxialcable or from the coaxial cable.

[0026] There is further provided a coaxial probe including (a) a coaxialcable including a first electrical conductor extending therethrough, (b)a first connector non-separatable from the coaxial cable, (c) a secondconnector detachably coupled to the first connector and including asecond electrical conductor extending therethrough and projectingtherefrom at an end thereof, the second electrical conductor beingelectrically connected to the first electrical conductor when the firstand second connectors are coupled to each other, (d) a planar waveguideon which the second electrical conductor projecting from the secondconnector is mounted, and (e) a sensor electrically connected to thesecond electrical conductor through the planar waveguide.

[0027] There is still further provided a coaxial probe including (a) acoaxial cable including an electrical conductor extending therethroughand projecting therefrom at an end thereof, (b) a planar waveguide onwhich the electrical conductor projecting from the coaxial cable ismounted, (c) a sensor electrically connected to the electrical conductorthrough the planar waveguide, (d) an electrically insulating sensorholder making contact with the sensor, and (e) a device for compressingthe sensor holder onto the sensor.

[0028] For instance, the device may be comprised of a screw. As analternative, the device may be comprised of a lever supported forrotation, and an actuator which actuates the lever such that the levercompresses the sensor holder onto the sensor.

[0029] There is yet further provided a coaxial probe including (a) acoaxial cable including an electrical conductor extending therethroughand projecting therefrom at an end thereof, (b) a planar waveguide onwhich the electrical conductor projecting from the coaxial cable ismounted, (c) a sensor electrically connected to the electrical conductorthrough the planar waveguide, (d) a sensor holder making contact withthe sensor, (e) a device for compressing the sensor holder onto thesensor, (f) a piezoelectric device incorporated in the sensor holder,and (g) an electrode terminal extending from the piezoelectric deviceoutwardly of the coaxial cable.

[0030] There is still yet further provided a coaxial probe including acoaxial cable including an electrical conductor extending therethroughand projecting therefrom at an end thereof, the electrical conductorincluding a bending portion and a sharpened tip end, the bending portiondefining a cantilever and the sharpened tip end defining a probe.

[0031] In another aspect of the present invention, there is provided ascanning micro-wave microscope including (a) one of the above-mentionedcoaxial probes, and (b) a controller. The sensor includes a cantileversupported at a distal end thereof on the planar waveguide, and a probemounted on a free end of the cantilever. The controller controls adistance between the probe and an object, based on a detection signalindicative of displacement of a free end of the cantilever, and scanninga surface of the object with the probe to thereby form an image of thesurface of the object.

[0032] The advantages obtained by the aforementioned present inventionwill be described hereinbelow.

[0033] In accordance with the present invention, it would be possible tomake the coaxial probe approach a surface of an object at a distancewhich is a general level in an interatomic-force microscope, and measurean electric capacity along irregularities of a surface of an object.

[0034] In addition, since it would be possible to exchange a sensor tobe used in an ineratomic-force microscope, into another one, a coaxialprobe suitable to measurement could be selected.

[0035] The above and other objects and advantageous features of thepresent invention will be made apparent from the following descriptionmade with reference to the accompanying drawings, in which likereference characters designate the same or similar parts throughout thedrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0036]FIG. 1 is a block diagram of a scanning probe microscope inaccordance with an embodiment of the present invention.

[0037]FIG. 2A is a cross-sectional view of a coaxial probe in accordancewith the first embodiment.

[0038]FIG. 2B is a side view of a coaxial probe in accordance with thefirst embodiment.

[0039]FIG. 3A is a cross-sectional view of a coaxial probe in accordancewith the second embodiment.

[0040]FIG. 3B is a side view of a coaxial probe in accordance with thesecond embodiment.

[0041]FIG. 4A is a cross-sectional view of a coaxial probe in accordancewith the third embodiment.

[0042]FIG. 4B is a side view of a coaxial probe in accordance with thethird embodiment

[0043]FIG. 5A is a cross-sectional view of a coaxial probe in accordancewith the fourth embodiment

[0044]FIG. 5B is a side view of a coaxial probe in accordance with thefourth embodiment.

[0045]FIG. 6A is a cross-sectional view of a coaxial probe in accordancewith the fifth embodiment.

[0046]FIG. 6B is a side view of a coaxial probe in accordance with thefifth embodiment.

[0047]FIG. 7A is a cross-sectional view of a coaxial probe in accordancewith the sixth embodiment.

[0048]FIG. 7B is a side view of a coaxial probe in accordance with thesixth embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0049] Preferred embodiments in accordance with the present inventionwill be explained hereinbelow with reference to drawings.

[0050]FIG. 1 is a block diagram of a scanning micro-wave microscope inaccordance with a preferred embodiment of the present invention.

[0051] The scanning micro-wave microscope is comprised of a measurementunit which measures physical quantity of an object 325, based onmicro-wave resonance, and a controller.

[0052] The measurement unit is comprised of a coaxial probe or coaxialresonator 100, a micro-wave oscillator 329, a directional coupler 330,and a detector 331.

[0053] The coaxial probe 100 includes a coaxial cable 108 including anelectrical conductor 107 extending centrally therethrough and projectingtherefrom at an end of the coaxial cable 108, and a sensor 109electrically connected to the electrical conductor 107.

[0054] The sensor 109 is comprised of a cantilever 109 a, and a probe109 b mounted on a free end of the cantilever 109 a.

[0055] The controller is comprised of a laser beam source 320, adivision photodiode 321, a position detector 322, an error amplifier323, a feedback controller 324, a first actuator 326, a second actuator328, and a central processing unit (CPU) 327.

[0056] The controller detects a signal indicative of a bendingdisplacement of the cantilever 109 a, controls a distance between theprobe 109 a and the object 325, based on the detected detection signal,and scans a surface of the object 325 with the probe 109 b to therebyform an image of a surface of the object 325. Specifically, thecontroller detects a bending displacement of the cantilever 109 a undera principle of optical lever by emitting a laser beam to a tip end ofthe cantilever 109 a, and controls a relative distance between theobject 325 and the probe 109 b with a resolution in a sub-nanometerorder. In addition, the controller scans the object 325 with the probe109 b to thereby measure topography and a resonance characteristicrelating to electric coupling of the coaxial probe 100 with the object325.

[0057] Hereinbelow is explained an operation of the scanning micro-wavemicroscope including the coaxial probe 100.

[0058] As illustrated in FIG. 1, the laser beam source 320 emits a laserbeam to a tip end of the cantilever 109 a. A laser beam reflected at thetip end of the cantilever 109 a is received in the division photodiode321, and the division photodiode 321 transmits a signal to the positiondetector 322 accordingly.

[0059] The position detector 322 transmits a signal Vc indicative of adisplacement of a tip end of the cantilever 109 a, to the erroramplifier 323, based on the signal transmitted from the divisionphotodiode 321.

[0060] The error amplifier 323 receives both the signal Vc and a signalVsp indicative of a predetermined value. The error amplifier 323amplifies a difference between the signals Vc and Vsp.

[0061] A signal indicative of the thus amplified difference istransmitted to the first actuator 326 through the feedback controller324. Based on the signal, the first actuator 326 controls a relativedistance between the probe 109 b and the object 325.

[0062] While a relative distance between the probe 109 b and the object325 is controlled in the above-mentioned manner, the central processingunit 327 instructs the micro-wave oscillator 329 to transmit amicro-wave to the coaxial cable 108 through the directional coupler 330.The micro-wave causes electric resonance in a coaxial resonator definedby the coaxial cable 108.

[0063] The detector 331 detects an amplitude of the reflected laser beamtransmitted from the coaxial cable 108 through the directional coupler330. Based on the thus detected amplitude, the central processing unit327 keeps a resonance frequency of the micro-wave oscillator 329 at acenter of resonance. As a result, the coaxial probe 100 is keptresonated.

[0064] The central processing unit 327 transmits a signal to the secondactuator 328 for scanning the object 325, and receives control signalstransmitted to the first actuator 326, relating to irregularities of asurface of the object 325. In addition, the central processing unit 327receives both a micro-wave frequency or a resonance frequency necessaryfor keeping the coaxial probe 100 resonated, and an output signaltransmitted from the detector 331, indicative of an amplitude of thereflected micro-wave, and forms images of irregularities of a surface ofthe object 325, based on those frequency and signals.

[0065] Hereinbelow are explained embodiments of the coaxial probe 100constituting a part of the scanning micro-wave microscope in accordancewith the embodiment.

[0066]FIG. 2A is a cross-sectional view of the coaxial probe 110 inaccordance with the first embodiment, and FIG. 2B is a side view of thecoaxial probe 110.

[0067] The coaxial probe 110 is comprised of a coaxial cable 108including an electrical conductor 107 extending therethrough andprojecting therefrom at an end thereof, a planar waveguide 101 on whichthe electrical conductor 107 projecting from the coaxial cable 108 ismounted, and a sensor electrically connected to the electrical conductor107 through the planar waveguide 101.

[0068] The planar waveguide 101 is comprised of a substrate 101 a havinga size of 4 mm×4 mm, and a strip line 101 b formed on the substrate 101a.

[0069] The sensor 109 is comprised of a cantilever 109 a supported at adistal end thereof on the planar waveguide 101, and a probe 109 bmounted on a free end of the cantilever 109 a.

[0070] The sensor 109 is excited at a frequency close to a resonancefrequency of a movement of the cantilever 109 a.

[0071] The probe 109 b having a sharpened tip end is incorporated intothe electrical conductor 107.

[0072] The strip line 101 b is electrically connected at one end to thecantilever 109 a through In alloy and at the other end to the electricalconductor 107.

[0073] A support 105 having a size of 1 mm×2 mm and a thickness of 0.5mm fixes the cantilever 109 a at the distal end of the cantilever 109 aonto the planar waveguide 101.

[0074] The support 105 and the cantilever 109 a are located on anextension of the electrical conductor 107 and are inclined relative toan axis of the electrical conductor 107. This arrangement ensures thateven if the probe 109 b is made approach the object 325 at a closedistance, the coaxial cable 108 and the substrate 101 a would not makecontact with the object 325.

[0075] In accordance with the coaxial probe 110, it would be possible tomake the probe 109 a approach a surface of the object 325 at a distancewhich is a general level in an interatomic-force microscope, and measurean electric capacity along irregularities of a surface of the object325.

[0076]FIG. 3A is a cross-sectional view of the coaxial probe 120 inaccordance with the second embodiment, and FIG. 3B is a side view of thecoaxial probe 120.

[0077] The coaxial probe 120 is comprised of a coaxial cable 108including a first electrical conductor (not illustrated) extendingtherethrough, a first connector 108 a non-separatable from the coaxialcable 108, a second connector 200 detachably coupled to the firstconnector 108 a and including a second electrical conductor (notillustrated) extending therethrough and projecting therefrom at an endthereof, a planar waveguide 101 on which the second electrical conductorprojecting from the second connector 200 is mounted, and a sensor 109electrically connected to the second electrical conductor through theplanar waveguide 101.

[0078] The second electrical conductor is electrically connected to thefirst electrical conductor when the first and second connectors 108 aand 200 are coupled to each other, The planar waveguide 101 is comprisedof a substrate 101 a having a size of 4 mm×4 mm, and a strip line 101 bformed on the substrate 101 a.

[0079] The sensor 109 is comprised of a cantilever 109 a supported at adistal end thereof on the planar waveguide 101, and a probe 109 bmounted on a free end of the cantilever 109 a.

[0080] The sensor 109 is excited at a frequency close to a resonancefrequency of a movement of the cantilever 109 a.

[0081] The probe 109 b having a sharpened tip end is incorporated intothe second electrical conductor.

[0082] The strip line 101 b is electrically connected at one end to thecantilever 109 a through In alloy and at the other end to the secondelectrical conductor.

[0083] A support 105 having a size of 1 mm×2 mm and a thickness of 0.5mm fixes the cantilever 109 a at the distal end of the cantilever 109 aonto the planar waveguide 101.

[0084] The support 105 and the cantilever 109 a are located on anextension of the electrical conductor 107 and are inclined relative toan axis of the electrical conductor 107. This arrangement ensures thateven if the probe 109 b is made approach the object 325 at a closedistance, the coaxial cable 108 and the substrate 101 a would not makecontact with the object 325.

[0085] In accordance with the coaxial probe 110, it would be possible tomake the probe 109 a approach a surface of the object 325 at a distancewhich is a general level in an interatomic-force microscope, and measurean electric capacity along irregularities of a surface of the object325.

[0086] In addition, since it would be possible to exchange the sensor109 and the planar waveguide 101 into others by exchanging the secondconnector 200 into another one.

[0087]FIG. 4A is a cross-sectional view of the coaxial probe 130 inaccordance with the third embodiment, and FIG. 4B is a side view of thecoaxial probe 130.

[0088] Whereas the sensor 109 is integral with the planar waveguide 101in the coaxial probe 110 in accordance with the first embodiment, thesensor 109 is designed detachable from the planar waveguide 101 in thecoaxial probe 130 in accordance with the third embodiment.

[0089] The coaxial probe 130 is comprised of a coaxial cable 108including an electrical conductor 107 extending therethrough andprojecting therefrom at an end thereof, a planar waveguide 101 on whichthe electrical conductor 107 projecting from the coaxial cable 108 ismounted, a sensor 109 electrically connected to the electrical conductor107 through the planar waveguide 101, a support 105 which fixes thesensor 109 onto the planar waveguide 101, an electrically insulatingsensor holder 111 making contact with the support 105, and a screw 112for compressing the sensor holder 111 onto the support 105.

[0090] The planar waveguide 101 is comprised of a substrate 101 a havinga size of 4 mm×4 mm, and a strip line 101 b formed on the substrate 101a.

[0091] The sensor 109 is comprised of a cantilever 109 a supported at adistal end thereof on the planar waveguide 101, and a probe 109 bmounted on a free end of the cantilever 109 a.

[0092] The sensor 109 is excited at a frequency close to a resonancefrequency of a movement of the cantilever 109 a.

[0093] The probe 109 b having a sharpened tip end is incorporated intothe electrical conductor 107.

[0094] The strip line 101 b is electrically connected at one end to thecantilever 109 a through In alloy and at the other end to the electricalconductor 107.

[0095] The support 105 fixes the cantilever 109 a at the distal end ofthe cantilever 109 a onto the planar waveguide 101.

[0096] The support 105 and the cantilever 109 a are located on anextension of the electrical conductor 107 and are inclined relative toan axis of the electrical conductor 107. This arrangement ensures thateven if the probe 109 b is made approach the object 325 at a closedistance, the coaxial cable 108 and the substrate 101 a would not makecontact with the object 325.

[0097] In accordance with the coaxial probe 110, it would be possible tomake the probe 109 a approach a surface of the object 325 at a distancewhich is a general level in an interatomic-force microscope, and measurean electric capacity along irregularities of a surface of the object325.

[0098] In addition, since it would be possible to exchange the sensor109 into another one by exchanging the coaxial probe 130 into anotherone.

[0099]FIG. 5A is a cross-sectional view of the coaxial probe 140 inaccordance with the fourth embodiment, and FIG. 5B is a side view of thecoaxial probe 140.

[0100] The coaxial probe 140 has the same structure as the structure ofthe coaxial probe 130 in accordance with the third embodiment, andadditionally includes a piezoelectric device 113 incorporated into thesensor holder 111, and an electrode terminal 114 extending from thepiezoelectric device 113 outwardly of the coaxial cable 108.

[0101] The piezoelectric device 113 is formed integrally in the sensorholder 111 with electrodes being sandwiched between the piezoelectricdevice 113 and the sensor holder 111. The electrodes are grounded. Thescrew 112 compresses the sensor holder 111 and the piezoelectric device113 onto the support 105, and electrically connects the cantilever 109 ato the strip line 101 b.

[0102] In accordance with the coaxial probe 140, the coaxial probe 140can be taken out by releasing the screw 112. In addition, application ofa ac voltage having a frequency close to a resonance frequency of thecoaxial probe 140 to the electrode terminal 114 would cause a bendingdisplacement in the probe 109 b which is resonant to the coaxial probe140, ensuring the probe 109 b makes periodical contact with a surface ofthe object 325.

[0103]FIG. 6A is a cross-sectional view of the coaxial probe 150 inaccordance with the fifth embodiment, and FIG. 6B is a side view of thecoaxial probe 150.

[0104] The coaxial probe 150 is comprised of a coaxial cable 108including an electrical conductor 107 extending therethrough andprojecting therefrom at an end thereof, a planar waveguide 101 on whichthe electrical conductor 107 projecting from the coaxial cable 108 ismounted, a sensor 109 electrically connected to the electrical conductor107 through the planar waveguide 101, a support 105 which fixes thesensor 109 onto the planar waveguide 101, an electrically insulatingsensor holder 111 making contact with the support 105, a lever 116supported at a center thereof such that the lever 116 can swing aboutthe center thereof, and a leaf spring 115 applying a force to the lever116 such that the lever 116 compresses the sensor holder The planarwaveguide 101 is comprised of a substrate 101 a having a size of 4 mm×4mm, and a strip line 101 b formed on the substrate 101 a.

[0105] The sensor 109 is comprised of a cantilever 109 a supported at adistal end thereof on the planar waveguide 101, and a probe 109 bmounted on a free end of the cantilever 109 a.

[0106] The sensor 109 is excited at a frequency close to a resonancefrequency of a movement of the cantilever 109 a.

[0107] The probe 109 b having a sharpened tip end is incorporated intothe electrical conductor 107.

[0108] The sensor 109 is compressed by the leaf spring 115 through thelever 116 and the sensor holder 111 to thereby be electrically connectedto the strip line 101 b.

[0109] By incorporating the piezoelectric device 113 into the sensorholder 111 in the same manner as the fourth embodiment, resonant bendingoscillation could be caused to the probe 109 b.

[0110] In accordance with the fifth embodiment, the coaxial probe 150can be released by rotating the lever 116 about the center against aresilient force exerted by the leaf spring 115.

[0111]FIG. 7A is a cross-sectional view of the coaxial probe 160 inaccordance with the sixth embodiment, and FIG. 7B is a side view of thecoaxial probe 160.

[0112] The coaxial probe 160 includes a coaxial cable 108 having anelectrical conductor 107 extending therethrough and projecting therefromat an end thereof.

[0113] The electrical conductor 107 includes a bending portion and asharpened tip end. The bending portion defines a cantilever 109 a andthe sharpened tip end defining a probe 109 b.

[0114] The coaxial probe 160 can provide the same advantages as theadvantages presented by the coaxial probe 110 in accordance with thefirst embodiment, even though the coaxial probe 160 has a simplerstructure than the structure of the coaxial probe 110.

[0115] While the present invention has been described in connection withcertain preferred embodiments, it is to be understood that the subjectmatter encompassed by way of the present invention is not to be limitedto those specific embodiments. On the contrary, it is intended for thesubject matter of the invention to include all alternatives,modifications and equivalents as can be included within the spirit andscope of the following claims.

[0116] The entire disclosure of Japanese Patent Application No.2000-119516 filed on Apr. 20, 2000 including specification, claims,drawings and summary is incorporated herein by reference in itsentirety.

What is claimed is:
 1. A coaxial probe comprising: (a) a coaxial cable including an electrical conductor extending therethrough and projecting therefrom at an end thereof; (b) a planar waveguide on which said electrical conductor projecting from said coaxial cable is mounted; and (c) a sensor electrically connected to said electrical conductor through said planar waveguide.
 2. The coaxial probe as set forth in claim 1, wherein said planar waveguide is comprised of: (b1) a substrate; and (b2) a strip line formed on said substrate, said strip line being electrically connected at one end to said sensor and at the other end to said electrical conductor.
 3. The coaxial probe as set forth in claim 1, wherein said planar waveguide is comprised of: (b1) a substrate; and (b2) a coplanar line formed on said substrate, said strip line being electrically connected at one end to said sensor and at the other end to said electrical conductor.
 4. The coaxial probe as set forth in claim 1, wherein said sensor is comprised of: (c1) a cantilever supported at a distal end thereof on said planar waveguide; and (c2) a probe mounted on a free end of said cantilever.
 5. The coaxial probe as set forth in claim 4, further comprising a support which fixes said cantilever at said distal end of said cantilever onto said planar waveguide.
 6. The coaxial probe as set forth in claim 5, wherein said support and said cantilever are located on an extension of said electrical conductor and are inclined relative to an axis of said electrical conductor.
 7. The coaxial probe as set forth in claim 1, wherein said sensor is excited at a frequency close to a resonance frequency of a movement of said cantilever.
 8. The coaxial probe as set forth in claim 1, wherein said sensor is detachable from said coaxial cable.
 9. The coaxial probe as set forth in claim 1, wherein said support is detachable from said coaxial cable.
 10. A coaxial probe comprising: (a) a coaxial cable including a first electrical conductor extending therethrough; (b) a first connector non-separatable from said coaxial cable; (c) a second connector detachably coupled to said first connector and including a second electrical conductor extending therethrough and projecting therefrom at an end thereof, said second electrical conductor being electrically connected to said first electrical conductor when said first and second connectors are coupled to each other; (d) a planar waveguide on which said second electrical conductor projecting from said second connector is mounted; and (e) a sensor electrically connected to said second electrical conductor through said planar waveguide.
 11. The coaxial probe as set forth in claim 10, wherein said planar waveguide is comprised of: (b1) a substrate; and (b2) a strip line formed on said substrate, said strip line being electrically connected at one end to said sensor and at the other end to said electrical conductor.
 12. The coaxial probe as set forth in claim 10, wherein said planar waveguide is comprised of: (b1) a substrate; and (b2) a coplanar line formed on said substrate, said strip line being electrically connected at one end to said sensor and at the other end to said electrical conductor.
 13. The coaxial probe as set forth in claim 10, wherein said sensor is comprised of: (c1) a cantilever supported at a distal end thereof on said planar waveguide; and (c2) a probe mounted on a free end of said cantilever.
 14. The coaxial probe as set forth in claim 13, further comprising a support which fixes said cantilever at said distal end of said cantilever onto said planar waveguide.
 15. The coaxial probe as set forth in claim 14, wherein said support and said cantilever are located on an extension of said second electrical conductor and are inclined relative to an axis of said second electrical conductor.
 16. The coaxial probe as set forth in claim 10, wherein said sensor is excited at a frequency close to a resonance frequency of a movement of said cantilever.
 17. A coaxial probe comprising: (a) a coaxial cable including an electrical conductor extending therethrough and projecting therefrom at an end thereof; (b) a planar waveguide on which said electrical conductor projecting from said coaxial cable is mounted; (c) a sensor electrically connected to said electrical conductor through said planar waveguide; (d) an electrically insulating sensor holder making contact with said sensor, and (e) means for compressing said sensor holder onto said sensor.
 18. The coaxial probe as set forth in claim 17, wherein said planar waveguide is comprised of: (b1) a substrate; and (b2) a strip line formed on said substrate, said strip line being electrically connected at one end to said sensor and at the other end to said electrical conductor.
 19. The coaxial probe as set forth in claim 17, wherein said planar waveguide is comprised of: (b1) a substrate; and (b2) a coplanar line formed on said substrate, said strip line being electrically connected at one end to said sensor and at the other end to said electrical conductor.
 20. The coaxial probe as set forth in claim 17, wherein said sensor is comprised of: (c1) a cantilever supported at a distal end thereof on said planar waveguide; and (c2) a probe mounted on a free end of said cantilever.
 21. The coaxial probe as set forth in claim 17, further comprising a support which fixes said cantilever at said distal end of said cantilever onto said planar waveguide, said sensor holder making contact with said support and said means compressing said sensor holder onto said support.
 22. The coaxial probe as set forth in claim 21, wherein said support and said cantilever are located on an extension of said electrical conductor and are inclined relative to an axis of said electrical conductor.
 23. The coaxial probe as set forth in claim 17, wherein said sensor is excited at a frequency close to a resonance frequency of a movement of said cantilever.
 24. The coaxial probe as set forth in claim 17, wherein said means is comprised of a screw.
 25. The coaxial probe as set forth in claim 17, wherein said means is comprised of a lever supported for rotation, and an actuator which actuates said lever such that the lever compresses said sensor holder onto said sensor.
 26. A coaxial probe comprising: (a) a coaxial cable including an electrical conductor extending therethrough and projecting therefrom at an end thereof; (b) a planar waveguide on which said electrical conductor projecting from said coaxial cable is mounted; (c) a sensor electrically connected to said electrical conductor through said planar waveguide; (d) a sensor holder making contact with said sensor; (e) means for compressing said sensor holder onto said sensor; (f) a piezoelectric device incorporated in said sensor holder; and (g) an electrode terminal extending from said piezoelectric device outwardly of said coaxial cable.
 27. A coaxial probe comprising a coaxial cable including an electrical conductor extending therethrough and projecting therefrom at an end thereof, said electrical conductor including a bending portion and a sharpened tip end, said bending portion defining a cantilever and said sharpened tip end defining a probe.
 28. A scanning micro-wave microscope comprising: (a) a coaxial probe; and (b) a controller, said coaxial probe including: (a1) a coaxial cable including an electrical conductor extending therethrough and projecting therefrom at an end thereof; (a2) a planar waveguide on which said electrical conductor projecting from said coaxial cable is mounted; and (a3) a sensor electrically connected to said electrical conductor through said planar waveguide, said sensor including a cantilever supported at a distal end thereof on said planar waveguide, and a probe mounted on a free end of said cantilever, said controller controlling a distance between said probe and an object, based on a detection signal indicative of displacement of a free end of said cantilever, and scanning a surface of said object with said probe to thereby form an image of said surface of said object.
 29. The scanning micro-wave microscope as set forth in claim 28, wherein said planar waveguide is comprised of: (b1) a substrate; and (b2) a strip line formed on said substrate, said strip line being electrically connected at one end to said sensor and at the other end to said electrical conductor.
 30. The scanning micro-wave microscope as set forth in claim 28, wherein said planar waveguide is comprised of: (b1) a substrate; and (b2) a coplanar line formed on said substrate, said strip line being electrically connected at one end to said sensor and at the other end to said electrical conductor.
 31. The scanning micro-wave microscope as set forth in claim 30, wherein said coaxial probe further includes a support which fixes said cantilever at said distal end of said cantilever onto said planar waveguide.
 32. The scanning micro-wave microscope as set forth in claim 31, wherein said support and said cantilever are located on an extension of said electrical conductor and are inclined relative to an axis of said electrical conductor.
 33. The scanning micro-wave microscope as set forth in claim 28, wherein said sensor is excited at a frequency close to a resonance frequency of a movement of said cantilever.
 34. A scanning micro-wave microscope comprising: (a) a coaxial probe; and (b) a controller, said coaxial probe including: (a1) a coaxial cable including a first electrical conductor extending therethrough; (a2) a first connector non-separatable from said coaxial cable; (a3) a second connector detachably coupled to said first connector and including a second electrical conductor extending therethrough and projecting therefrom at an end thereof, said second electrical conductor being electrically connected to said first electrical conductor when said first and second connectors are coupled to each other; (a4) a planar waveguide on which said second electrical conductor projecting from said second connector is mounted; and (a5) a sensor electrically connected to said electrical conductor through said planar waveguide, said sensor including a cantilever supported at a distal end thereof on said planar waveguide, and a probe mounted on a free end of said cantilever, said controller controlling a distance between said probe and an object, based on a detection signal indicative of displacement of a free end of said cantilever, and scanning a surface of said object with said probe to thereby form an image of said surface of said object.
 35. The scanning micro-wave microscope as set forth in claim 34, wherein said planar waveguide is comprised of: (b1) a substrate; and (b2) a strip line formed on said substrate, said strip line being electrically connected at one end to said sensor and at the other end to said electrical conductor.
 36. The scanning micro-wave microscope as set forth in claim 34, wherein said planar waveguide is comprised of: (b1) a substrate; and (b2) a coplanar line formed on said substrate, said strip line being electrically connected at one end to said sensor and at the other end to said electrical conductor.
 37. The scanning micro-wave microscope as set forth in claim 36, wherein said coaxial probe further includes a support which fixes said cantilever at said distal end of said cantilever onto said planar waveguide.
 38. The scanning micro-wave microscope as set forth in claim 37, wherein said support and said cantilever are located on an extension of said second electrical conductor and are inclined relative to an axis of said second electrical conductor.
 39. The scanning micro-wave microscope as set forth in claim 34, wherein said sensor is excited at a frequency close to a resonance frequency of a movement of said cantilever.
 40. A scanning micro-wave microscope comprising: (a) a coaxial probe; and (b) a controller, said coaxial probe including: (a1) a coaxial cable including an electrical conductor extending therethrough and projecting therefrom at an end thereof; (a2) a planar waveguide on which said electrical conductor projecting from said coaxial cable is mounted; (a3) a sensor electrically connected to said electrical conductor through said planar waveguide; (a4) an electrically insulating sensor holder making contact with said sensor; and (a5) means for compressing said sensor holder onto said sensor, said sensor including a cantilever supported at a distal end thereof on said planar waveguide, and a probe mounted on a free end of said cantilever, said controller controlling a distance between said probe and an object, based on a detection signal indicative of displacement of a free end of said cantilever, and scanning a surface of said object with said probe to thereby form an image of said surface of said object.
 41. The scanning micro-wave microscope as set forth in claim 40, wherein said planar waveguide is comprised of: (b1) a substrate; and (b2) a strip line formed on said substrate, said strip line being electrically connected at one end to said sensor and at the other end to said electrical conductor.
 42. The scanning micro-wave microscope as set forth in claim 40, wherein said planar waveguide is comprised of: (b1) a substrate; and (b2) a coplanar line formed on said substrate, said strip line being electrically connected at one end to said sensor and at the other end to said electrical conductor.
 43. The scanning micro-wave microscope as set forth in claim 40, wherein said coaxial cable further includes a support which fixes said cantilever at said distal end of said cantilever onto said planar waveguide, said sensor holder making contact with said support and said means compressing said sensor holder onto said support.
 44. The scanning micro-wave microscope as set forth in claim 43, wherein said support and said cantilever are located on an extension of said electrical conductor and are inclined relative to an axis of said electrical conductor.
 45. The scanning micro-wave microscope as set forth in claim 40, wherein said sensor is excited at a frequency dose to a resonance frequency of a movement of said cantilever.
 46. The scanning micro-wave microscope as set forth in claim 40, wherein said means is comprised of a screw.
 47. The scanning micro-wave microscope as set forth in claim 40, wherein said means is comprised of a lever supported for rotation, said lever swinging downwardly to thereby compress said sensor holder.
 48. A scanning micro-wave microscope comprising: (a) a coaxial probe; and (b) a controller, said coaxial probe including: (a1) a coaxial cable including an electrical conductor extending therethrough and projecting therefrom at an end thereof; (a2) a planar waveguide on which said electrical conductor projecting from said coaxial cable is mounted; (a3) a sensor electrically connected to said electrical conductor through said planar waveguide; (a4) a sensor holder making contact with said sensor; (a5) means for compressing said sensor holder onto said sensor; (a6) a piezoelectric device incorporated in said sensor holder; and (a7) an electrode terminal extending from said piezoelectric device outwardly of said coaxial cable, said sensor including a cantilever supported at a distal end thereof on said planar waveguide, and a probe mounted on a free end of said cantilever, said controller controlling a distance between said probe and an object, based on a detection signal indicative of displacement of a free end of said cantilever, and scanning a surface of said object with said probe to thereby form an image of said surface of said object.
 48. A scanning micro-wave microscope comprising: (a) a coaxial probe comprising a coaxial cable including an electrical conductor extending therethrough and projecting therefrom at an end thereof, said electrical conductor including a bending portion and a sharpened tip end, said bending portion defining a cantilever and said sharpened tip end defining a probe; and (b) a controller, said controller controlling a distance between said probe and an object, based on a detection signal indicative of displacement of a free end of said cantilever, and scanning a surface of said object with said probe to thereby form an image of said surface of said object. 